1. Field of the Invention
The present invention relates to a flat panel display apparatus with input function, and more particularly to an integrated electromagnetic type input flat panel display apparatus.
2. Description of Related Art
Touch panel technologies which Integrate touch control techniques into a display apparatus have been developed as an important and major trend of the display technology. Comparing to the conventional display apparatus with display function only, the display apparatus with a touch panel constitutes the communicating interface between the user and a host. For example, users may input desired information to the host using a touch panel integrated with the display apparatus while watching images displayed by the display apparatus. Allowing users to input desired information to the host via a display surface of the display apparatus, a touch panel substantially reduces or eliminates the need for other types of input devices such as keyboards, mice, and the like. Currently, touch panels have been widely integrated with display surfaces of flat panel display apparatuses such as liquid crystal display (LCD), plasma display panel (PDP), electroluminescence (EL) display, organic light emitting display (OLED), and electronic paper display (EPD), etc.
Depending on the type of contact object used such as a user's finger, a digital pen or a stylus, etc., and depending on the manner in which the location, of a contact point (i.e., the location or the distance where the contact object is operably proximate the touch panel) is determined, touch control technologies are generally classifiable as resistive-type, capacitive-type, electromagnetic-type, and infrared-type touch control technologies.
The advantage of the resistive-type, capacitive-type, and infrared-type touch control technologies is to allow a user to operate and input information with user's fingers. However, for hand writing by using a digital pen or a stylus, there are several problems. When user's hand or palm resting on the touch panel's surface, one major problem for the resistive-type, capacitive-type, and infrared-type touch control technologies is that these three kinds of technologies cannot easily distinguish the stylus between user's palms. Furthermore, the resistive-type and capacitive-type touch modules placed on the display panel such as an LCD panel will reduce the rate of transmission and increase the reflection of light so as to degrade the optical characteristics of the display apparatus.
Electromagnetic-type touch control technique is usually applied in coordinate input apparatuses such as digitizers. The coordinate input apparatus includes sensor coils or antennas arranged along x and y axes constituting a sensor plane and a coordinate indicator such as a stylus with a resonance circuit (without battery) or a self powered digital pen. The coordinates of the indicator are obtained through signal transmitting and receiving between the indicator and the sensor coils. There is a trend of integrating electromagnetic-type input technique into the display apparatus to overcome the problems for hand writing application to distinguish the digital pen or the stylus between user's palm or finger approaching the display surface. Moreover, since the sensor plane is placed under the display panel, the sensor plane will not degrade the optical characteristics of the display apparatus. Therefore, the electromagnetic-type input technique is so far the best hand writing technique to be integrated into the display apparatus. Nevertheless, since the trend of modern flat panel display is to develop light and thin display apparatus, both for large size flat display and small size electronic paper display, placing the sensor plane under the display panel does not meet the requirement of modern flat panel display. Moreover, although placing the sensor plane under the display panel will not degrade the optical characteristics of the display apparatus additional printed circuit board with sensor coils or antennas is needed which increases the weight and cost of the display apparatus. Finally, there are problems of alignment between the display panel and the printed circuit board with sensor coils or antennas or determination of location of the narrow edges of the display apparatus during manufacture.
In order to solve the above-mentioned drawbacks of the conventional flat panel display apparatus with input function, an integrated electromagnetic type input flat panel display apparatus is thus provided.